Biology subjects

Palanisamy, N.

Publications and source records attributed to Palanisamy, N..

17 recordsLinked to original sources

bioRxiv2025

Mapping Molecular Diversity in Prostate Cancer with a Combined Multiplex IHC and RNA-ISH Assay

Combining multiplex Immunohistochemistry (mIHC) and RNA in situ hybridization (RNA-ISH) in a single assay allows for the simultaneous detection of multiple markers in tissue sections. This approach can be a powerful tool for understanding the molecular landscape of tumors, such as prostate cancer, by providing information in the same tissue context. Studying the expression of multiple genes in the same tissue is often necessary. ERG, SPINK1, ETV1, and ETV4 are all relevant genes in the context of prostate cancer. ERG is a transcription factor, and its fusion with the TMPRSS2 gene is one of the most common genetic alterations in prostate cancer. Overexpression of the ERG protein due to this gene, involved in gene fusion with TMPRSS2 and rarely with other 5 partner genes, can be detected using Immunohistochemistry (IHC) due to the availability of a characterized antibody. SPINK1 (serine peptidase inhibitor, Kazal type 1) is an overexpressed protein in a subset of prostate cancers that do not harbor ERG rearrangements. High SPINK1 expression is known to be associated with a more aggressive tumor phenotype in some studies. SPINK1 expression can be detected using a well-characterized antibody by IHC. ETV1 and ETV4 are transcription factors that can also be involved in gene fusions in prostate cancer, albeit less frequently than ERG. There are no well-characterized antibodies for ETV1 and ETV4. Due to the mutually exclusive expression of ERG, SPINK1, ETV1, and ETV4, simultaneous evaluation of these genes can provide valuable information on the molecular subtype of prostate cancer, which can have implications for the assessment of inter- and intra-tumor heterogeneity, prognosis, and potential treatment. We describe a novel approach for the simultaneous evaluation of all four markers in prostate cancer tissues using a combined dual IHC and dual RNA-ISH method using validated antibodies for ERG, SPINK1, and RNAscope probes for ETV1 and ETV4.

pathology↗

bioRxiv2025

Chromosome segregation in Escherichia coli involves DNA binding by the MinC-MinD complex

The Escherichia coli Min system, composed of the proteins MinC, MinD, and MinE, is crucial for directing septum formation at mid-cell. MinD has also been shown to bind DNA in a non-sequence-specific manner and to tether plasmid DNA to liposomes. A role for the Min system in chromosome segregation has been proposed, whereby repeated, transient membrane-tethering events mediated by MinD could help prevent backward movements of the duplicated chromosomes once entropic forces weaken. However, the contribution of the other Min proteins to DNA binding has remained unclear. Here, we demonstrate that DNA binding is strongly enhanced when MinD and MinC form a complex, while MinE and FtsZ (at high concentrations) interfere with this binding. We reveal a critical role for the linker connecting MinCs N- and C-terminal domains in both DNA binding and inhibition of FtsZ polymerization. E. coli strains expressing MinC linker variants from the native locus, in combination with the alpha subunit of HU tagged with GFP, display chromosomes that appear more spread throughout the cell. This phenotype could reflect reduced compaction, chromosome segregation defects, or a combination of both. These findings suggest a previously unrecognized role for the MinC linker in DNA binding and provide new insights into a potential physiological role of MinCD-DNA bnding in chromosome organization and/or dynamics.

microbiology↗

bioRxiv2023

Role of Adenosine Deaminase in Prostate Cancer Progression

Prostate cancer (PCa) is the second most common cancer and constitutes about 14.7% of total cancer cases. PCa is highly prevalent and more aggressive in African American (AA) men when compared to European-American (EA) men. PCa tends to be a highly heterogeneous malignancy with a complex biology that is not fully understood. We use metabolomics as a tool to understand the mechanisms behind PCa progression and disparities in its clinical outcome. A key enzyme in the purine metabolic pathway, Adenosine deaminase (ADA) was found upregulated in PCa. ADA was also associated with higher-grade PCa and poor disease-free survival. The inosine-to-adenosine ratio which is a surrogate for ADA activity was high in the urine of PCa patients and higher in AA PCa compared to EA PCa. To understand the significance of high ADA in PCa, we established ADA overexpression models and performed various in vitro and in vivo studies. Our studies have revealed that an acute increase in the expression of ADA during later stages of tumor development enhances in vivo growth in multiple pre-clinical models. Further analysis reveals that this tumor growth could be driven by the activation of mTOR signaling. Chronic ADA overexpression shows alterations in the cells adhesion machinery and a decrease in the adhesion potential of the cells to the extracellular matrix in vitro. Loss of cell-matrix interaction is critical for metastatic dissemination, suggestive of ADAs role in promoting metastasis. This is consistent with the association of higher ADA expression with higher-grade tumors and poor patient survival. Overall, our findings suggest that increased ADA expression may promote PCa progression, specifically tumor growth and metastatic dissemination.

cancer biology↗

bioRxiv2023

An integrative proteomics approach identifies tyrosine kinase KIT as a novel therapeutic target for SPINK1-positive prostate cancer.

Elevated Serine Peptidase Inhibitor, Kazal type 1 (SPINK1) levels in [~]10-25% of prostate cancer (PCa) patients associate with aggressive phenotype, for which there are limited treatment choices and dismal clinical outcomes. Using an integrative proteomics approach involving label-free phosphoproteome and proteome profiling, we delineated the downstream signaling pathways involved in SPINK1-mediated tumorigenesis in PCa, and identified tyrosine kinase KIT as a highly enriched kinase. Furthermore, high to moderate levels of KIT expression was detected in [~]85% of SPINK1-positive PCa specimens. KIT signaling regulates SPINK1-associated oncogenesis, and treatment with KIT inhibitor reduces tumor growth and distant metastases in preclinical mice models. Mechanistically, KIT signaling modulates WNT/{beta}-catenin pathway and confers stemness-related features in PCa. Notably, inhibiting KIT signaling restores AR/REST levels, forming a feedback loop enabling SPINK1 repression. Overall, we uncover the role of KIT signaling downstream of SPINK1 in maintaining lineage plasticity and provide new treatment modalities for advanced-stage SPINK1-positive subtype.

cancer biology↗

bioRxiv2023

Transcriptional regulation of Dyskerin via canonical WNT signaling modulates sphingolipid biosynthesis and drives colorectal cancer.

Targeting EGFR has been effective in RAS/RAF wild-type colorectal cancer (CRC) patients. However, residual tumor relapses, necessitating the importance of biomarker-guided novel therapeutics. We show elevated DKC1 in [~]88% of CRC patients with poor recurrence-free survival. Clinically, DKC1-positive patients exhibit similarity with CMS2 class, the canonical subtype with active WNT signaling. We show functional significance of DKC1 in cell proliferation, stemness, DNA repair, and survival. Further, mice bearing DKC1 knockdown xenografts show [~]81% reduction in tumor burden. Mechanistically, WNT/{beta}-catenin signaling orchestrates DKC1 expression, then, DKC1/SOX2 complex regulates SGPP2, modulating sphingolipids metabolism. Downregulation of DKC1 in CRC lead to reduced SGPP2 levels leading to dysregulation of sphingolipid biosynthesis. Of note, DKC1-high CRC patients show accumulation of ceramides, namely C23 and C24, signifying their utility in diagnosis. Collectively, we delineate the mechanistic circuitry involved in DKC1-mediated CRC progression, propose ceramides as biomarker, and underscore WNT-based therapeutics for DKC1-positive patients.

cancer biology↗

bioRxiv2023

Identification of functional Npu DnaE and gp41-1 inteins split in three fragments

Inteins are special proteins that auto-catalytically carry out a protein splicing reaction. Due to their ability to post-translationally modify target proteins in vitro and in vivo, they are used in different applications, ranging from protein purification to the construction of Boolean logic gates. So far inteins have been found to be either encoded by a single gene (contiguous inteins) or by two separate ones (split inteins). Previously, it has been shown that the contiguous Ssp and Rma DnaB inteins and the split Npu DnaE intein could be artificially split in three fragments and retain functionality. Here we report the identification of novel split sites within the N-terminal fragments of the Npu DnaE and gp41-1 split inteins that lead to synthetic functional three-piece versions of these inteins. These variants contribute to the toolkit of three-piece inteins that could be used in biotechnological applications based on highly-fragmented inteins.

molecular biology↗

bioRxiv2022

Brief Report: Prognostic relevance of 3q amplification in squamous cell carcinoma of the lung

IntroductionAmplification of 3q is the most common genetic alteration identified in squamous cell carcinoma of the lung (LUSC) with the most frequent amplified region being 3q26-3q28. MethodsIn this analysis, we aim to describe the prognostic relevance of 3q by focusing on a minimal common region (MCR) of amplification within 3q constituted by 25 genes. We analyzed 511 cases of LUSC from The Cancer Genome Atlas (TCGA) and included 476 in the final analysis. ResultsWe identified a 25-gene MCR that was amplified in 221 (44.3%) cases and was associated with better disease specific-survival (DSS) (NR versus 9.25 years; 95% CI [5.24-NR]; log-rank p=0.011) and a progression-free interval (PFI) of 8 years (95% CI [5.1-NR]) versus 4.9 years (95% [3.5-NR]) (Log-rank p=0.020). Multivariable analysis revealed MCR amplification was associated with improved DSS and PFI. ConclusionAmplification of the 25-gene MCR within 3q was present in 44% of this cohort mainly composed of Caucasian patients with early-stage LUSC. This analysis is a strong indicator of the prognostic relevance of the 25-gene MCR within 3q. We are further evaluating its prognostic relevance in a racially diverse patient population with advanced LUSC.

genomics↗

bioRxiv2021

Expanding the SiMPl plasmid toolbox for use with spectinomycin/streptomycin

We recently developed the SiMPl plasmid toolbox, which is constituted by pairs of plasmids, generically indicated as pSiMPlx_N and pSiMPlx_C, which can be stably maintained in Escherichia coli with a single antibiotic x. The method exploits the split intein gp41-1 to reconstitute the enzyme conferring resistance towards the antibiotic x, whereby each enzyme fragment is expressed from one of the plasmids in the pair. pSiMPl plasmids are currently available for use with ampicillin, kanamycin, chloramphenicol, hygromycin and puromycin. Here we introduce another pair for use with spectinomycin/streptomycin broadening the application spectrum of the SiMPl toolbox. To find functional splice sites in aminoglycoside adenylyltransferase we apply a streamlined strategy looking exclusively at the flexibility of native cysteine and serine residues, which we first validated splitting the enzymes conferring resistance towards ampicillin, kanamycin, chloramphenicol and hygromycin. This strategy could be used in the future to split other enzymes conferring resistance towards antibiotics.

synthetic biology↗

bioRxiv2020

Transcriptional network involving ERG and AR orchestrates Distal-Less Homeobox 1 mediated prostate cancer progression.

Nearly half of the prostate cancer (PCa) cases show elevated levels of ERG oncoprotein due to TMPRSS2-ERG gene fusion. Here, we demonstrate ERG mediated upregulation of Distal-less homeobox-1 (DLX1), an established PCa biomarker. Using series of functional assays, we show DLX1 elicits oncogenic properties in prostate epithelial cells, and abrogating its function leads to reduced tumor burden in mouse xenografts. Clinically, [~]60% of the PCa patients exhibit high DLX1 levels, while [~]50% of these cases also harbor elevated ERG associated with aggressive disease and poor survival probability. Mechanistically, we show that ERG gets recruited onto DLX1 promoter and interacts with its enhancer-bound androgen receptor (AR) and FOXA1 to regulate DLX1 expression in TMPRSS2-ERG positive cases. Alternatively, in ERG-negative cases, DLX1 is regulated by AR/AR-V7 and FOXA1. Importantly, BET bromodomain inhibitors disrupt the transcriptional regulators of DLX1 and its associated oncogenic properties, signifying their efficacy in treatment of DLX1-positive PCa patients.

cancer biology↗

bioRxiv2020

An inducible AraC that responds to blue light instead of arabinose

In Escherichia coli, the operon responsible for the catabolism of L-arabinose is regulated by the dimeric DNA-binding protein AraC. In the absence of L-arabinose, AraC binds to the distal I1 and O2 half-sites, leading to repression of the downstream PBAD promoter. In the presence of the sugar, the dimer changes conformation and binds to the adjacent I1 and I2 half-sites, resulting in the activation of PBAD. Here we engineer blue light-inducible AraC dimers in Escherichia coli (BLADE) by swapping the dimerization domain of AraC with blue light-inducible dimerization domains. Using BLADE to overexpress proteins important for cell shape and division site selection, we reversibly control cell morphology with light. We demonstrate the exquisite light responsiveness of BLADE by employing it to create bacteriographs with an unprecedented quality. We then employ it to perform a medium-throughput characterization of 39 E. coli genes with poorly defined or completely unknown function. Finally, we expand the initial library and create a whole family of BLADE transcription factors (TFs), which we characterize using a novel 96-well light induction setup. Since the PBAD promoter is commonly used by microbiologists, we envisage that the BLADE TFs will bring the many advantages of optogenetic gene expression to the field of microbiology.

microbiology↗

bioRxiv2020

C-terminal eYFP fusion impairs Escherichia coli MinE function

The Escherichia coli Min system plays an important role in the proper placement of the septum ring (Z-ring) at mid-cell during cell division. MinE forms a pole-to-pole spatial oscillator together with the membrane-bound ATPase MinD, which results in MinD having a concentration gradient with maxima at the poles and minimum at mid-cell. MinC, the direct inhibitor of the Z-ring initiator protein FtsZ, forms a complex with MinD at the membrane, thus mirroring MinD polar gradients. Therefore, MinC-mediated FtsZ inhibition occurs away from mid-cell. The existence of the oscillations was revealed by performing time-lapse microscopy with fluorescently-labeled Min proteins. These fusion proteins have been since then widely used to study properties of the Min system. Here we show that, despite permitting oscillations to occur in a range of protein concentrations, the enhanced yellow fluorescent protein (eYFP) C-terminally fused to MinE impairs its function. Combining in vivo, in vitro and in silico approaches, we demonstrate that the eYFP compromises MinE ability to displace MinC from MinD, to stimulate MinD ATPase activity and to directly bind to the membrane. Moreover, we reveal that MinE-eYFP is prone to aggregation. Taken together, our results indicate that this fusion is functionally impaired and should be used with caution in cell biological studies.

microbiology↗

bioRxiv2019

Clonal evaluation of prostate cancer molecular heterogeneity in biopsy samples by dual immunohistochemistry and dual RNA in situ hybridization

Prostate cancer is frequently multifocal. Although there may be morphological variation, the genetic underpinnings of each tumor are not clearly understood. To assess the inter and intra tumor molecular heterogeneity in prostate biopsy samples, we developed a combined immunohistochemistry and RNA in situ hybridization method for the simultaneous evaluation of ERG, SPINK1, ETV1, and ETV4. Screening of 601 biopsy cores from 120 consecutive patients revealed multiple alterations in a mutually exclusive manner in 37% of patients, suggesting multifocal tumors with considerable genetic differences. Furthermore, the incidence of molecular heterogeneity was higher in African Americans patients compared to Caucasian American patients. About 47% of the biopsy cores with discontinuous tumor foci showed clonal differences with distinct molecular aberrations. ERG positivity occurred predominantly in low Gleason grade cancer, whereas ETV4 expression was observed mostly in high Gleason grade cancer. Further studies revealed correlation between the incidence of molecular markers and clinical and pathologic findings, suggesting potential implications for diagnostic pathology practice, such as defining dominant tumor nodules and discriminating juxtaposed but molecularly different tumors of different grade patterns.

cancer biology↗

bioRxiv2019

Therapeutically actionable PAK4 is amplified, overexpressed and involved in bladder cancer progression

Muscle-invasive bladder carcinomas (MIBCs) are aggressive genitourinary malignancies. Disease incidence and survival rates vary based on aggressiveness and treatment options. Metastatic urothelial carcinoma of the bladder is generally incurable by current chemotherapy and leads to early mortality. For a minority ([~]20%) of patients, T-cell checkpoint inhibitors provide durable benefits following prior platinum therapy. Recent studies have identified molecular subtypes of MIBCs with different sensitivities to frontline therapy, suggesting heterogeneity in these tumors and pointing to the importance of molecular characterization of MIBCs to provide effective treatment. We have performed multi-omic profiling of the kinome to identify therapeutic targets that are overexpressed in a subset of BLCAs. Our analyses revealed amplification and overexpression of P21 (RAC1) activated kinase 4 (PAK4) in a subset of BLCAs. For these tumors, multiplex kinase assay profiling identified corresponding PAK4 target substrates. By performing experiments using cultured bladder cancer cells, we confirmed the role of PAK4 in BLCA cell proliferation and invasion. Furthermore, our studies showed that a PAK4 inhibitor was effective in curtailing growth of BLCA cells. Transcriptomic analyses identified elevated expression of another kinase, Protein Tyrosine Kinase 6 (PTK6), upon treatment with a PAK4 inhibitor. Similarly, RNA interference of PAK4 led to elevated expression of PTK6. Treatment with a combination of kinase inhibitors (vandetanib and dasatinib) showed enhanced sensitivity compared to either drug alone. Thus, PAK4 may be therapeutically actionable for a subset of MIBC patients with amplified and/or overexpressed PAK4 in their tumors. Our results also indicate that combined inhibition of PAK4 and PTK6 may overcome resistance to PAK4. These observations warrant clinical investigations with selected BLCA patients.

cancer biology↗

bioRxiv2019

Pseudogene associated recurrent gene fusion in prostate cancer

Analysis of next generation transcriptome sequencing data of prostate cancer identified a novel gene fusion formed by the fusion of a protein coding gene (KLK4) with a non-coding pseudogene (KLKP1) and expression of its cognate protein. Screening of 659 prostate cancer TMA showed about 32% of positive cases predominantly expressed in higher Gleason grade tumors. Concomitant expression with ERG but not with SPINK1 and other ETS fusion positive tumors. Fusion gene expression potentially regulated by AR and ERG. Antibody specific to the KLK4-KLKP1 fusion protein was validated by immunohistochemistry and western blot methods. Oncogenic properties were validated by in vitro and in vivo functional studies. Clinical data analysis shows significant association with prostate cancer in young men and overall survival analysis indicate favorable prognosis. Non-invasive detection in urine samples has been confirmed. Taken together, we present a novel biomarker for routine screening of high Gleason grade prostate cancer at diagnosis.\n\nSIGNIFICANCEWe discovered and validated a novel prostate cancer (PCa) specific fusion gene involving a protein coding (KLK4) and a pseudogene (KLKP1) and its cognate protein. The unique feature of this fusion gene is the conversion of the noncoding pseudogene into a protein coding gene and its unique expression only in about 30% of high Gleason grade PCa. Expression of this gene is found to be concomitant in ERG fusion positive prostate cancer but mutually exclusive with SPINK1, ETV1, ETV4 and ETV5 positive tumors. Like other ETS family gene fusions, KLK4-KLKP1 can be detected in the urine samples of patients with prostate cancer enabling non-invasive detection of high Gleason grade prostate cancer. Given the unique feature of this fusion oncogenic potential, high Gleason grade specific expression and noninvasive detection, this novel gene fusion has a potential to be used as a biomarker for early detection of high-grade prostate cancer and a therapeutic target.

cancer biology↗

bioRxiv2019

Clonal evaluation of early onset prostate cancer by expression profiling of ERG, SPINK1, ETV1, and ETV4 on whole mount radical prostatectomy tissue

Expression profiles of ETS related genes and SPINK1 in early onset prostate cancer have not been thoroughly explored. We retrieved 151 radical prostatectomy specimens from young men with prostate cancer (<55yrs) and characterized the expression of ERG, SPINK1, ETV1 and ETV4 by dual immunohistochemistry and dual RNA in-situ hybridization. Age, race, family history, preoperative prostate-specific antigen, biochemical recurrence and pathological variables using whole mount radical prostatectomy tissue were collected. 313 tumor nodules from 151 men including 68 (45%) Caucasians and 61 (40%) African Americans. Positive family history of prostate cancer was observed in 65 (43%) patients. Preoperative prostate-specific antigen ranged from 0.3 to 52.7 ng/ml (mean 7.04). Follow-up period ranged from 1 to 123.7 months (Mean 30.3). Biochemical recurrence was encountered in 8/151 (5%). ERG overexpression was observed in 85/151 (56%) cases, followed by SPINK1 in 61/151 (40%), ETV1 in 9/149 (6%), and ETV4 in 4/141 (3%). There were 25/151 (17%) cases showing both ERG and SPINK1 overexpression within different regions of either the same tumor focus or different foci. Higher frequency of ERG overexpression was seen in younger patients ([≤] 45 years old) (76% vs. 49%, p = 0.002213), Caucasian men (71% vs. 41% p = 0.000707), organ-confined tumors (64% vs. 33%, p = 0.00079), and tumors of Grade Groups 1 and 2 (62% vs. 26%, p = 0.008794). SPINK1 overexpression was more in African American men (68% vs. 26%, p = 0.00008), in tumors with high tumor volume (> 20%) and with anterior located tumors. ETV1 and ETV4 demonstrated rare overexpression in these tumors, particularly in the higher-grade tumors. This study expands the knowledge of the clonal evolution of multifocal cancer in young patients and support differences in relation to racial background and genetics of prostate cancer.

pathology↗

bioRxiv2019

Androgen deprivation upregulates SPINK1 expression and potentiates cellular plasticity in prostate cancer

The Serine Peptidase Inhibitor, Kazal type 1 (SPINK1) overexpression represents ~10-25% of the prostate cancer (PCa) cases associated with shorter recurrence-free survival and poor prognosis. Nonetheless, androgen-deprivation therapy (ADT) remains the mainstay treatment for locally advanced and metastatic PCa patients. However, majority of these individuals eventually progress to castration-resistant stage, and a subset of these patients develop ADT-induced neuroendocrine PCa. Despite adverse effects of ADT, possible role of androgen signaling in SPINK1-mediated prostate oncogenesis remains unexplored. Here, we show that androgen receptor (AR) and its corepressor, the RE1-silencing transcription factor (REST), occupy SPINK1 promoter and functions as a direct transcriptional repressor of SPINK1, thus blocking AR signaling via ADT relieves its repression, leading to SPINK1 upregulation. In agreement, an inverse association between SPINK1 levels and AR expression was observed across multiple PCa cohorts, and in neuroendocrine differentiated cells. While, lineage reprogramming factor SOX2 in turn binds to SPINK1 promoter leading to its transactivation in androgen-deprived conditions with concomitant increase in neuroendocrine markers. Additionally, we also confirm the role of SPINK1 in epithelial-mesenchymal transition, drug resistance, stemness and cellular plasticity. Moreover, we show that Casein Kinase 1 inhibitor stabilizes the REST levels, which in cooperation with AR, conjures transcriptional repression of SPINK1 expression, and impedes SPINK1-mediated oncogenesis. Collectively, our findings provide a plausible explanation to the paradoxical clinical outcomes of ADT, possibly due to increased SPINK1 levels. This study highlights the need to take a well-informed decision prior to ADT and develop alternative therapeutic strategies for castrate-resistant PCa patients.

cancer biology↗

bioRxiv2018

Polycomb Group protein EZH2-mediated transcriptional repression of microRNA-338/-421 drives SPINK1-positive prostate cancer

PurposeSerine Peptidase Inhibitor, Kazal type-1 (SPINK1) overexpression defines the second most recurrent and aggressive prostate cancer (PCa) subtype. However, the underlying molecular mechanism and pathobiology of SPINK1 in PCa remains largely unknown.\n\nExperimental DesignMicroRNA-prediction tools were employed to examine the SPINK1-3UTR for miRNAs binding. Luciferase reporter assays were performed to confirm the SPINK1-3UTR binding of shortlisted miR-338-5p/miR-421. Further, miR-338-5p/-421 overexpressing cancer cells (SPINK1-positive) were evaluated for oncogenic properties using cell-based functional assays and mice xenograft model. Global gene expression profiling was performed to unravel the biological pathways altered by miR-338-5p/-421. Immunohistochemistry and RNA in-situ hybridization was carried-out on PCa patients tissue microarray for SPINK1 and EZH2 expression respectively. Chromatin immunoprecipitation assay was performed to examine EZH2 occupancy on the miR-338-5p/-421 regulatory regions. Bisulfite sequencing and methylated DNA-immunoprecipitation was performed on PCa cell lines and patients specimens.\n\nResultsWe established a critical role of miRNA-338-5p/-421 in post-transcriptional regulation of SPINK1. Ectopic expression of miRNA-338-5p/-421 in SPINK1-positive PCa cells abrogate oncogenic properties including cell-cycle progression, stemness and drug resistance, and show reduced tumor burden and distant metastases in mice model. Importantly, we show SPINK1-positive PCa patients exhibit increased EZH2 expression, suggesting its role in miRNA-338-5p/-421 epigenetic silencing. Furthermore, presence of CpG dinucleotide DNA methylation marks on the regulatory regions of miR-338-5p/-421 in SPINK1-positive PCa cells and patients specimens confirms epigenetic silencing.\n\nConclusionOur findings revealed that miRNA-338-5p/-421 are epigenetically silenced in SPINK1-positive PCa, while restoring the expression of these miRNAs using epigenetic drugs or synthetic mimics could abrogate SPINK1-mediated oncogenesis.\n\nTRANSLATIONAL IMPACTWe establish a regulatory model involving the functional interplay between SPINK1, miRNA-338-5p/miRNA-421 and EZH2, thereby, revealing hitherto unknown mechanism of SPINK1 up-regulation in SPINK1-positive subtype. Our findings provide a strong rationale for the development of potential therapeutic strategies for SPINK1-positive malignancies. We demonstrate that restoring miRNA-338-5p/miRNA-421 expression using epigenetic drugs including DNMTs inhibitors in combination with HDACs or HKMTs inhibitors or miRNA synthetic mimics in SPINK1-positive prostate cancer abrogate SPINK1-mediated oncogenicity. The major findings of this study will not only advance the prostate cancer field, but will also be valuable for treatment and disease management of other SPINK1-positive malignancies.

cancer biology↗